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The "FAQ" page has been changed by QwertyManiac:
http://wiki.apache.org/hadoop/FAQ?action=diff&rev1=104&rev2=105
1. Restart the HDFS
== What does "file could only be replicated to 0 nodes, instead of 1" mean? ==
- The NameNode does not have any available !DataNodes. This can be caused by a wide variety
of reasons. Check the DataNode logs, the NameNode logs, network connectivity, ...
+ The NameNode does not have any available !DataNodes. This can be caused by a wide variety
of reasons. Check the DataNode logs, the NameNode logs, network connectivity, ... Please
see the page: CouldOnlyBeReplicatedTo
== If the NameNode loses its only copy of the fsimage file, can the file system be recovered
from the DataNodes? ==
No. This is why it is very important to configure [[http://hadoop.apache.org/hdfs/docs/current/hdfs-default.html#dfs.namenode.name.dir|dfs.namenode.name.dir]]
to write to two filesystems on different physical hosts, use the SecondaryNameNode, etc.